Genetic studies both at the organismal and cellular levels demand a sophisticated downstream analysis of the phenotypes that result from the genetic manipulations. The creation of the transgenic and knockout animals proposed in this application, as well as the greatly increased capabilities of investigators using cell culture models proposed by the proposed flow cytometry core, will greatly increase the need for evaluating cellular and tissue organization by state of the art microscopic methods. The optical sectioning capabilities of a confocal fluorescence microscope are ideal for these studies because they provide image data that allows a three dimensional reconstruction of structures. To accommodate the needs of this diverse group of investigators it is therefore proposed to significantly upgrade an existing facility equipped with a Zeiss 4100 Laser scanning microscope. While the facility has been of great use to researchers, the LSM-410 is capable of far greater imaging contrast resolution and sensitivity, than the existing electronics, software and filters will permit. The limitations of the current system are now posing an impediment to current and potential users of the facility, and it is critically necessary to upgrade the LSM-410. The upgrade will provide a significant increase in imaging contrast resolution, sensitivity and data acquisition and handling. Central to this will be an upgrade of the now obsolete software and hardware currently in place. It is also proposed to install a UV laser line that will allow multi-channel labeling, provide calcium imaging capabilities, and expand the selection of useful fluorophores. The core will be supervised by Gary Wessel, Associate Professor, an expert in the field of microscopy, who has a long track record of publications using the proposed technologies. On a day to day basis the core will be run by a highly trained technician, who will aid users in imaging and sample preparation. Users of this core facility will have access not only to a state of the art confocal microscope, but also to guidance, expertise and training towards applying this technology to their own research needs.